Differential pressure sensors provide an electronic signal as a result of measuring a difference between two pressures. One approach to measuring a differential pressure is to use two single-ended sensors where each sensor is “constrained” with a vacuum on one side of a diaphragm or movable membrane. This approach results in very large devices and is expensive, making it unsuitable for many end products such as inhalers or other portable consumer devices.
Another approach to measuring a differential pressure is to route the two pressures being measured to either side of a diaphragm or a movable membrane. Routing the two pressures to the membrane as well as connecting the electrical output of the membrane to a circuit often results in a complicated assembly that is also large and expensive.